A basic structural unit of a silicone polymer consists of silicon-oxygen chains, through silicon atoms, side chains are connected with other various organic groups. Compared with other polymer materials, the silicone polymer has the following outstanding properties: 1. Heat-resistance: a silicone product is constituted by a main chain of silicon oxygen (Si—O) bonds, therefore, silicone products have high temperature resistance, and the molecular bond will not break or decompose at a high temperature (or irradiation). 2. Weather resistance: the main chain of a silicone product consists of —Si—O—, which has better thermostability, radiation resistance, weather resistance and longer service life under natural environments. 3. Electrical insulation properties: a silicone product has good electrical insulation properties, its dielectric loss, withstand voltage, corona-resistance, volume resistivity and surface resistivity are all among the best in insulating materials, furthermore, its electrical performances are hardly effected by temperature and frequency. Thus, based on the aforementioned good properties, as a kind of silicone products, organopolysiloxane is widely used in LED photovoltaic industry.
CN103342816A describes a curable organopolysiloxane composition, which is used in LED lamp package and has the following advantages: excellent adhesion, high hardness, excellent thermal shock resistance, high transparency, etc.
Generally, a LED lamp package comprises a light-emitting component and a LED support, the light-emitting component is fixed on the LED support, the LED support is usually made of a metal substrate, the metal substrate is provided with a silver coating, and the silver coating is used for focusing or diffusing the light of the light-emitting component. By coating and curing the organopolysiloxane composition on the light-emitting component and the silver coating of the LED support, the packaging of LED lamp is basically completed. However, in the prior art, during the course of long-term use of the LED lamp package, sulfur in the ambient air will gradually erode to the silver coating, cause the silver coating to be vulcanized and tarnish, and further cause serious light attenuation; furthermore, in humid environments, the gradual penetration of moisture in the air can also cause problems of light-emitting components and seriously affect the lifetime of LED lamps.